We featured the Greenwich meridian two years ago on Google Sightseeing, so it’s about time we had a closer look at the other global zero: the equator. Although it is more than 40,000km long, there are surprisingly few towns along the line – much of its length consists of ocean, and on land it crosses large expanses of tropical rainforest. We start our journey, appropriately enough, in the country named after its location: Ecuador. Perhaps the best known monument marking the equator is Mitad del Mundo (Middle of the World), just outside the capital, Quito. These days, GPS-laden…